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HOW DOES THE SOFTWARE WORK?

HOW DOES A COMPUTER PROCESS INFORMATION? and What are the key differences between a diskette and a hard drive? | download free pdf
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MANAGING PUBLIC SECTOR RECORDS A Training Programme Understanding Computers: An Overview for Records and Archives Staff INTERNATIONAL INTERNATIONAL RECORDS COUNCIL ON ARCHIVES MANAGEMENT TRUST MANAGING PUBLIC SECTOR RECORDS: A STUDY PROGRAMME UNDERSTANDING COMPUTERS: AN OVERVIEW FOR RECORDS AND ARCHIVES STAFF MANAGING PUBLIC SECTOR RECORDS A STUDY PROGRAMME General Editor, Michael Roper; Managing Editor, Laura Millar UNDERSTANDING COMPUTERS: AN OVERVIEW FOR RECORDS AND ARCHIVES STAFF INTERNATIONAL RECORDS INTERNATIONAL MANAGEMENT TRUST COUNCIL ON ARCHIVES MANAGING PUBLIC SECTOR RECORDS: A STUDY PROGRAMME Understanding Computers: An Overview for Records and Archives Staff © International Records Management Trust, 1999. Reproduction in whole or in part, without the express written permission of the International Records Management Trust, is strictly prohibited. Produced by the International Records Management Trust 12 John Street London WC1N 2EB UK Printed in the United Kingdom. Inquiries concerning reproduction or rights and requests for additional training materials should be addressed to International Records Management Trust 12 John Street London WC1N 2EB UK Tel: +44 (0) 20 7831 4101 Fax: +44 (0) 20 7831 7404 E-mail: infoirmt.org Website: http://www.irmt.org Version 1/1999 MPSR Project Personnel Project Director Anne Thurston has been working to define international solutions for the management of public sector records for nearly three decades. Between 1970 and 1980 she lived in Kenya, initially conducting research and then as an employee of the Kenya National Archives. She joined the staff of the School of Library, Archive and Information Studies at University College London in 1980, where she developed the MA course in Records and Archives Management (International) and a post-graduate research programme. Between 1984 and 1988 she undertook an onsite survey of record-keeping systems in the Commonwealth. This study led to the foundation of the International Records Management Trust to support the development of records management through technical and capacity-building projects and through research and education projects. General Editor Michael Roper has had a wide range of experience in the management of records and archives. He served for thirty-three years in the Public Record Office of the United Kingdom, from which he retired as Keeper of Public Records in 1992. He has also taught on the archives courses at University College London and the University of British Columbia, Canada. From 1988 to 1992 he was Secretary General of the International Council on Archives and since 1996 he has been Honorary Secretary of the Association of Commonwealth Archivists and Records Managers (ACARM). He has undertaken consultancy missions and participated in the delivery of training programmes in many countries and has written extensively on all aspects of records and archives management. Managing Editor Laura Millar has worked extensively not only as a records and archives management consultant but also in publishing and distance education, as an editor, production manager and instructional designer. She received her MAS degree in archival studies from the University of British Columbia, Canada, in 1984 and her PhD in archival studies from the University of London in 1996. She has developed and taught archival education courses both in Canada and internationally, including at the University of British Columbia, Simon Fraser University and the University of Alberta. She is the author of a number of books and articles on various aspects of archival management, including A Manual for Small Archives (1988), Archival Gold: Managing and Preserving Publishers’ Records (1989) and A Handbook for Records Management and College Archives in British Columbia (1989). Project Steering Group Additional members of the Project Steering Group include Association of Records Managers and Administrators (ARMA International): Hella Jean Bartolo International Council on Archives: George MacKenzie Project Management Consultant: Tony Williams University College London: Elizabeth Shepherd Video Production Co-ordinator: Janet Rogers Educational Advisers Moi University: Justus Wamukoya Universiti Teknologi Mara: Rusnah Johare University of Botswana: Nathan Mnjama University of Ghana: Harry Akussah, Pino Akotia University of New South Wales: Ann Pederson University of West Indies: Victoria Lemieux Project Managers Lynn Coleman (1994-6) Laura Millar (1996-7) Elizabeth Box (1997-8) Dawn Routledge (1999) Production Team Additional members of the production team include Jane Cowan Nicki Hall Greg Holoboff Barbara Lange Jennifer Leijten Leanne Nash Donors The International Records Management Trust would like to acknowledge the support and assistance of the following: Association of Records Managers and Administrators (ARMA International) British Council British High Commission Ghana British High Commission Kenya Caribbean Centre for Development Administration (CARICAD) Canadian International Development Agency (CIDA) Commonwealth Secretariat Department for International Development (East Africa) Department for International Development (UK) DHL International (UK) Limited Foreign and Commonwealth Office Human Rights Fund Hays Information Management International Council on Archives Nuffield Foundation Organisation of American States Royal Bank of Scotland United Nations Development Program Understanding Computers: An Overview for Records and Archives Staff Principal Author KIMBERLY BARATA Kimberly Barata is a Research Officer and Consultant for the International Records Management Trust. She is a specialist in electronic records and has advised the Governments of Ghana, Malta and the Secretariat for the Commission for East African Co-operation. Prior to her appointment with the Trust, she was the UK Representative for Archives and Museum Informatics (A&MI) and a senior research fellow at the School of Library, Archive and Information Studies at University College London. Kimberly is a graduate of the University of Pittsburgh School of Information Sciences and participated in the latter end of the Functional Requirements for Recordkeeping Project. Contributors Elizabeth Box John McDonald Laura Millar Reviewers Terry Cook, (formerly) National Archives of Canada Tony Leviston, State Records Authority of New South Wales Testers Kenya National Archives and Documentation Service State Archives and Heraldic Services, South Africa CONTENTS Introduction 1 Lesson 1 An Introduction to Computer Technology 4 Lesson 2 Computing Environments 27 Lesson 3 Computer Applications 41 Lesson 4 What to Do Next? 55 FIGURES 1. Sample Home Page 35 2. Relational Tables 45 3. Examples of Data Records 46 4. Sample Electronic Mail Message 50 INTRODUCTION INTRODUCTION TO UNDERSTANDING COMPUTERS: AN OVERVIEW FOR RECORDS AND ARCHIVES STAFF This introductory module is designed as support for other MPSR modules in the series that refer to the use of computers to varying degrees. It aims to familiarise those who may be unacquainted with some of these basic computer concepts. As well as describing the concepts associated with computer technology, this module explains some of the key terms students will encounter as they establish relationships with specialists in the information technology community. Understanding Computers: An Overview for Records and Archives Staff should be read before the other computer-related modules in this programme, Automating Records Services and Managing Electronic Records, as much of the basic information important to those modules is introduced here and so is not explained in those modules. This module includes the following lessons: Lesson 1: An Introduction to Computer Technology Lesson 2: Computing Environments Lesson 3: Computer Applications Lesson 4: What to Do Next?. AIMS AND OUTCOMES Aims This module has six primary aims. These are to 1. introduce the key components of a computer system (hardware, software, data) 2. acquaint readers with how computers work UNDERSTANDING COMPUTERS 1 3. present the basic concepts of various computing environments 4. give a broad view of how technology is improving communications through the use of electronic mail and the Internet. 5. discuss the various kinds of storage media and recording formats and methods commonly associated with a computer 6. explain how to obtain more information on computerisation. Outcomes At the end of this module, you should understand 1. the key components of a computer system (hardware, software, data) 2. the basics of how computers work 3. the basic concepts of various computing environments 4. how technology is improving communications 5. the various kinds of storage media and recording formats and methods available 6. where to go for more information on computerisation. METHOD OF STUDY AND ASSESSMENT This module of four lessons should occupy about 45 hours of your time. You should plan to spend about: 15 hours on Lesson 1 12 hours on Lesson 2 10 hours on Lesson 3 8 hours on Lesson 4. This includes time spent doing the reading and considering the study questions. At the end of each lesson there is a summary of the major points. Sources for additional information are provided in Lesson 5. Throughout each lesson, activities have been included to help you think about the information provided. Each activity is a ‘self-assessed’ project; there is no ‘right’ or ‘wrong’ answer. Rather, the activity is designed to encourage you to explore the ideas UNDERSTANDING COMPUTERS 2 presented and relate them to the environment in which you are studying or working. If you are studying these modules independently and are not part of a records or archives management organisation, you should try to complete the activities with a hypothetical situation if possible. If the activity suggests writing something, you should keep this brief and to the point; this is not a marked or graded exercise and you should only spend as much time on the activity as you feel necessary to understand the information being taught. At the end of each lesson are comments on the activities that will help you assess your work. Following the summary at the end of each lesson are a number of self-study questions. Note that these self-study questions are designed to help you review the material in this module. They are not intended to be graded or marked exercises. You should complete as many of the questions as you feel will help you to understand the concepts presented. External assessments, such as assignments or exams, will be included separately when this module becomes part of a graded educational programme. ADDITIONAL RESOURCES This module discusses basic computer concepts, and it is not necessary to be working in a records office, records centre or archival institution to understand the information conveyed here. However, this module is intended to introduce ideas of importance for later discussions of records issues, so readers are encouraged to think of the records issues involved as they work through these lessons. The various activities may ask you to draw on your own experiences and compare those with the information provided in the lessons. If you do not have access to facilities that allow you to create real scenarios for activities, you may need to develop a fictitious scenario for your activities. Alternately, you may wish to discuss this module with friends or colleagues who work with computers so that you can discuss principles and concepts with them and compare your understanding with theirs. UNDERSTANDING COMPUTERS 3 LESSON 1 AN INTRODUCTION TO COMPUTER TECHNOLOGY This lesson introduces key concepts related to how computers work. Computer- related terms are defined and basic computer functions are explained. In particular, the following topics are addressed. • What is a computer? • What are the components of a computer? • How does a computer work? • How does the software work? • How does a computer process information? • How does the computer’s memory work? • How is data stored? • Why is documentation important? • What are viruses? Please remember, this introductory lesson is not intended to provide a comprehensive explanation of the technical details of computerisation. Information is provided in order to introduce you to key computer concepts and provide an overview of computerisation. The average computer user, as apposed to those pursuing a career in computing, do not need to know more than the information provided here in order to work effectively with information technologies. UNDERSTANDING COMPUTERS 4 WHAT IS A COMPUTER? A computer allows users to store and process information quickly and automatically. A computer is a programmable machine. It allows the user to store all sorts of information and then ‘process’ that information, or data, or carry out actions with the information, such as calculating numbers or organising words. Computer: A machine that can receive and store information and change or process it. Information: Knowledge that is communicated. Data (pl.): The representation of information in a formalised manner suitable for communication, interpretation and processing, generally by a computer system. Note: the term ‘raw data’ refers to unprocessed information. Computers can be generally classified by size and power, although there can be considerable overlap. Following are descriptions of several different types of computers. Mainframe computers are large-sized, powerful multi-user computers that can support concurrent programs. That means, they can perform different actions or ‘processes’ at the same time. Mainframe computers can be used by as many as hundreds or thousands of users at the same time. Large organisations may use a mainframe computer to execute large-scale processes such as processing the organisation’s payroll. Mini-computers are mid-sized multi-processing computers. Again, they can perform several actions at the same time and can support from 4 to 200 users simultaneously. In recent years the distinction between mini-computers and small mainframes has become blurred. Often the distinction depends upon how the manufacturer wants to market its machines. Organisations may use a mini-computer for such tasks as managing the information in a small financial system or maintaining a small database of information about registrations or applications. Workstations are powerful, single-user computers. They have the capacity to store and process large quantities of data, but they are only used by one person at a time. However, workstations are typically linked together to form a computer network called a local area network, which means that several people, such as staff in an office, can communicate with each other and share electronic files and data. UNDERSTANDING COMPUTERS 5 Computer network: A grouping of computers and peripherals connected together by telecommunications links to enable a group of users to share and exchange information. Networks are discussed in more detail later in this module. A workstation is similar to a personal computer but is more powerful and often comes with a higher-quality monitor. In terms of computing power, workstations lie in between personal computers and mini-computers. Workstations commonly support applications that require relatively high-quality graphics capabilities and a lot of memory, such as desktop publishing, software development and engineering applications. Personal computers (PCs), also called microcomputers, are the most popular type of computer in use today. The PC is a small-sized, relatively inexpensive computer designed for an individual user. Today, the world of PCs is basically divided between IBM-compatible and Macintosh-compatible machines, named after the two computer manufacturers. Computers may be called ‘desktop’ computers, which stay on the desk, or ‘laptop’ computers, which are lightweight and portable. Organisations and individuals use PCs for a wide range of tasks, including word processing, accounting, desktop publishing, preparation and delivery of presentations, organisation of spreadsheets and database management. Entry-level PCs are much more powerful than a few years ago, and today there is little distinction between PCs and workstations. Activity 1 If your office has computers, find out the type or types. Are they mainframe computers, mini-computers, workstations or personal computers? What ‘processes’ or actions are the computers used for? Write a brief description of the types of computers in place and their main uses. If your office has more than one type of computer, find out why? What different tasks are the different computers intended to do? If your office does not have computers, try to contact a colleague or friend who has a computer and ask him or her what type he or she has and what primary functions it is used for. UNDERSTANDING COMPUTERS 6 WHAT ARE THE COMPONENTS OF A COMPUTER? Computers are made up of two parts: the hardware and the software. Hardware: The physical equipment required to create, use, manipulate and store electronic data. Software: The computerised instructions that operate a computer, manipulate the data and execute particular functions or tasks. All computers require the following hardware components: • central processing unit (CPU) Central processing unit (CPU): The chip or chips at the heart of a computer that enable it to process data. Also known as a processor. • memory Memory: An area within a computer system that holds data waiting to be processed. • storage device Storage device: The place where a computer puts data. • input devices : the devices that allow data and instructions to enter a computer (such as a keyboard, mouse, scanner) Input: Any resource required for the functioning of a process, in the course of which it will be transformed into one or more outputs. • output devices: the devices that allow information to be represented (that is, given out) to the user, such as a display screen or printer) Output: The product of the transformation of inputs by a process. UNDERSTANDING COMPUTERS 7 Printers, scanners and external disk drives that may be connected to the computer are also sometimes called ‘peripheral devices’. Peripheral device: Any piece of equipment in a computer system that is not actually inside the computer itself. The central processing unit (CPU) is the heart of the computer. It carries out all of the instructions given in a program, such as a word processing or spreadsheet program. The CPU consists of one or more chips (another name for “integrated circuits”). Chip: A small piece of semi-conducting material (such as silicon) about 1 centimetre (¼ inch) square on which an integrated circuit is embedded. An integrated circuit is a number of electronic components joined together to form a path for electricity. Central processing unit chips contain the circuits representing the CPU. A microprocessor is a particular type of chip. The original IBM personal computer used the Intel 8088 microprocessor. Most of today’s microcomputers are designed around a microprocessor from one of two product families: x86 or Power. The 80286, 80386, and 80486 models that followed were referred to by the last three digits, 286, 386, and 486. For the next generation, however, Intel broke with tradition and introduced the Pentium in 1993. In 1997, it introduced the Pentium II to address multi-media applications, and most recently the Pentium III to address the new opportunities provided by access to large volumes of information on the world wide Web. Other manufacturers of chips (such as Cyrix) produce chips of similar power and capabilities. CPU’s are not all equal. Some process data faster than others. A computer contains a system clock that emits pulses to establish the timing of all systems operations. The system clock operates at a speed quite different from a clock that keeps track of the time of the day. The system clock determines the speed at which the computer can execute an instruction, and therefore limits the number of instructions the computer can complete within a specific amount of time. The time to complete an instruction execution cycle is measured in megahertz (MHz) or millions of cycles per second. Although some instructions require multiple cycles to complete, the processor speed should be thought of in terms of the number of instructions the processor can execute in one second. Today, microprocessor speeds exceed 300 MHz. If all other specifications are identical, then higher megahertz ratings means faster processing. When determining what type of computer you are using or considering what type of computer to acquire, it is important to know that these terms – 286, 386, 486, Pentium – refer to the type of processor in the computer. Newer computers will come with Pentium microprocessors (or the equivalent from other manufacturers); older ones with microprocessors from the x86 family. UNDERSTANDING COMPUTERS 8 It is important to know the type of processor in your computer. Some newer computer programs will not run on older processors, and some newer processors are too sophisticated for older software. The faster the processor in a computer, the more quickly the computer will perform operations. The most common type of memory that most users are familiar with is ‘main memory’ or ‘RAM’ (random-access memory). Random access memory (RAM): An area in the computer system unit that temporarily holds a user’s data, operating system instructions and program instructions. The word ‘main’ is used to distinguish it from external mass storage devices such as the hard drive or disk drives. Note that the term ‘mass storage’ refers to various techniques and devices for storing large amounts of data; mass storage is distinct from memory because it retains data even when the computer is turned off. Thus mass storage is sometimes referred to as ‘auxiliary storage’. Following are definitions of common storage devices: Storage: The area within a computer system where data can be left on a longer term basis while it is not needed for processing. Diskette. A small, removable, flexible mylar plastic disk covered with a thin layer of a magnetisable substance, onto which digital data can be recorded and stored. Also known as a floppy disk. Hard drive: The storage area within the computer itself, where megabytes of space are available to store bits of information. Also known as a hard disk. Optical disk: A storage device that uses reflecting surfaces and laser technology to read and write data on a disk. Also known as a laser disk. Magnetic tape: A continuous plastic strip covered with magnetic oxide; the tape is divided into parallel tracks onto which data may be recorded by selectively magnetising parts of the surface, or spots, in each of the tracks. The data can then be stored and reused. UNDERSTANDING COMPUTERS 9 Activity 2 If your office has a microcomputer, look at the manuals that come with it. Review the manuals to find out what type of microprocessor is in the computer. Look also at the computer screen when the computer is turned on to see if information about the computer is shown there. Then examine two types of software used by your organisation. What are the minimum requirements for a microprocessor for each type of software? Does the computer meet the minimum requirements for the software? Does it exceed the requirements (that is, is the computer’s microprocessor newer or more powerful than the software requires)? Again, look in the software manuals for information, or ask a friend or colleague to help you. Do not remove the back from the computer or try to unload or reload the software. HOW DOES A COMPUTER WORK? A computer functions in the following manner: • The computer accepts input. Computer input is whatever is entered or fed into a computer system. Input can be supplied by a person (such as by using a keyboard) or by another computer or device (such as a diskette or CD-ROM). Some examples of input include the words and symbols in a document, numbers for a calculation, instructions for completing a process, pictures, and so on. • The computer performs useful operations, manipulating the data in many ways. This manipulation is called processing. Examples of processing include performing calculations, sorting lists of words or numbers, modifying documents and pictures according to user instructions, and drawing graphs. A computer processes data in the CPU. Process: A systematic series of actions a computer uses to manipulate data. • The computer stores data. A computer must store data so that it is available for processing. Most computers have more than one location for storing data (the hard drive or C:\, and the floppy drive or A:\). The place where the computer stores the data depends on how the data is being used. The computer puts the data in one place while it is waiting to be processed and another place when it is not needed for immediate processing. The storage of data in the computer is called ‘online storage’ while the storage of data on computer tapes, diskettes or CD-ROMs is called ‘offline storage’. UNDERSTANDING COMPUTERS 10